The PCI Express card uses RME's own audio bus, operating in combination with Multiface II, Multiface, Digiface and the RPM DJ interface. RME interface can be easily expanded so that it operates with the latest and fastest PCI Express computers and Windows Vista. It can be used directly with RME's Time Code Option Module, offering an SMPTE controlled operation. RME's HDSPe PCI card is not based on a PCI to PCI Express bridge, which would simply add PCIe to existing PCI technology. It is a newly developed genuine PCI Express solution, which consequently takes full advantage of the new format, achieving significant performance gains in multitrack audio.

The PCI Express interface of the HDSP system is based on the PCI Express Base Specification v 1.1. It represents a 1-Lane PCI Express Endpoint Device and supports 2.5 Gbps line speed. Thanks to the packet-based full duplex communication, the card provides a transfer rate of up to 500 MB/s - 250 MB/s in every direction.

The connection between PCI card and I/O box is established using ordinary firewire cable (IEEE 1394, 6-pole.) The data transfer does not use Firewire protocol, but our own proprietary bus protocol. The supplied cable is 4.5 m (15 ft.) long. The PCI card operates as power supply for the attached I/O-box (Digiface, Multiface, Multiface II, RPM) over the FireWire cable.